■ Chronic systemic infection caused
by the spirochete T. pallidum,
transmitted through skin and
mucosa, with manifestations in
nearly every organ system.
■ Incidence is approximately 30,000
cases annually
■ Primary infection: A painless ulcer
or chancre on the mucocutaneous
site of inoculation. Associated with
regional lymphadenopathy
(chancriform syndrome: distal ulcer
associated with proximal
lymphadenopathy).
■ Systemic infection: Shortly after
inoculation, syphilis becomes a
systemic infection with
characteristic secondary and tertiary
stages.
■ Course: Clinical course and response
to standard therapy may be altered
in HIV/AIDS.
Venereal syphilis caused by T.
pallidum. T. pallidum is a thin
delicate spirochete with 6–14
spirals. Only natural host for T.
pallidum is the human. Subspecies
of T. pallidum cause the nonvenereal
diseases endemic syphilis (bejel),
yaws, and pinta
Transmission. Sexual contact: Contact
with infectious lesion (chancre,
mucous patch, condyloma latum,
cutaneous lesions of secondary
syphilis). Sixty percent of contacts
of persons with primary and
secondary syphilis become infected.
Congenital infection: In utero or
perinatal transmission.
The spirochetes pass through intact
mucous membrane and microscopic
abrasion in skin, enter lymphatics
and blood within a few hours, and
produce systemic infection and
metastatic foci before development
of a primary lesion. Spirochetes
divide locally,
Spirochetes divide locally, with
resulting host inflammatory response
and chancre formation, either a
single lesion or, less commonly,
multiple lesions. Cellular immunity
is of major importance in healing of
early lesions and control of infection
(TH1 type).
Dark-Field Microscopy. Positive in
primary chancre and papular lesions
of secondary syphilis such as
condylomata lata. Unreliable in oral
cavity because of the presence of
saprophytic spirochetes, and
negative in patients treated
systemically or topically with
antibiotics.
Regional lymph node aspirated and
aspirate examined in the dark-field
microscope. Direct Fluorescent
Antibody T. pallidum (DFATP) Test
Fluorescent antibodies are used to
detect T. pallidum in exudate from
lesion, lymph node aspirate, or
tissue.
Serologic Tests for Syphilis (STS).
Positive in persons with any
treponemal infection. Tests always
positive in secondary syphilis.
Nontreponemal STS. Measures IgG
and IgM directed against cardiolipin–
lecithin–cholesterol antigen
complex. Rapid plasma reagin (RPR)
test (automated RPR: ART).
VDRL slide test; nonreactive in 25% of
patients with primary syphilis. In
early syphilis: either do fluorescent
treponemal antibody-absorbed (FTAABS) test or repeat VDRL in 1–2
weeks if initial VDRL negative.
Prozone phenomenon: if antibody
titer high, test may be negative;
must dilute serum; becomes
nonreactive or reactive in lower
titers following therapy for early
syphilis.
Treponemal STS FTA-ABS Test.
Agglutination assays for antibodies
to T. pallidum:
Microhemagglutination assay (MHATP; Serodia TPPA test); T. pallidum
hemagglutination test (TPHA). Often
remain reactive after therapy; not
helpful in determining infectious
status of patient with past syphilis.
Dermatopathology. In primary and
secondary syphilis, lesional skin
biopsy shows central thinning or
ulceration of epidermis.
Lymphocytic and plasmacytic dermal
infiltrate. Proliferation of capillaries
and lymphatics with endarteritis;
may have thrombosis and small
areas of necrosis. Dieterle stain
demonstrates spirochetes.
Genital or extragenital lesions occur
at sites of inoculation. Ulcers are
usually painless unless secondarily
infected. Incubation period: 21 days
(average); range, 10–90 days.
Chancre Button-like papule develops
at the site of inoculation into a
painless erosion and then ulcerates
with raised border and scanty serous
exudate . Surface may be crusted.
Lesions few millimeters to 1 or 2 cm
in diameter. Usually single lesions;
less commonly, few, multiple, or
kissing lesions. Extragenital chancres
occur at any site of inoculatlon;
lesions on the fingers may be
painful.
Sites of Predilection. Genital sites are
most common. Male: inner prepuce,
coronal sulcus of the glans penis,
shaft, base. Female: cervix, vagina,
vulva, clitoris, breast; chancres
observed less frequently in women.
Extragenital chancres: anus or
rectum, mouth, lips, tongue tonsils,
fingers (painful!), toes, breast,
nipple.
Lymphadenopathy. Appears within 7
days. Nodes are discrete, firm,
rubbery, nontender, and more
commonly unilateral; may persist for
months.
Differential Diagnosis Genital
Erosion/Ulcer. GH, traumatic ulcer,
fixed drug eruption, chancroid,
lymphogranuloma venereum (LGV).
Diagnosis Clinical suspicion,
confirmed by dark-field microscopy
or serologically.
Treatment Intramuscular benzathine
penicillin G 2.4 million units in
single dose or oral doxycycline 100
mg twice daily for 14 days.
Appears 2–6 months after primary
infection; 2–10 weeks after
appearance of the primary chancre;
6–8 weeks after healing of chancre.
Chancre may still be present when
secondary lesions appear (15% of
cases) . Concomitant HIV infection
may alter course of secondary
syphilis. Fever, sore throat,
Concomitant HIV infection may alter
course of secondary syphilis. Fever,
sore throat, weight loss, malaise,
anorexia, headache, meningismus.
Mucocutaneous lesions are
asymptomatic.
Skin Lesions of Secondary Syphilis.
Macules and papules 0.5–1 cm,
round to oval; pink brownish-red.
First exanthem always macular and
faint. Later eruptions may be
papulosquamous, pustular, or
acneiform. Vesiculobullous lesions
occur only in neonatal congenital
syphilis (palms and soles).
On palpation, papules are firm;
condylomata lata, soft. Lesions may
be annular or polycyclic, especially
on face in dark-skinned persons. In
relapsing secondary syphilis,
arciform lesions. Always sharply
defined except for macular
exanthem. Lesions are scattered,
tend to remain discrete, and usually
symmetric
Condylomata lata : most commonly in
anogenital region and mouth; can be
seen on any body surface where
moisture can accumulate between
intertriginous surfaces, i.e., axillae
or toe webs.
Hair. Diffuse hair loss, including
temples and parietal scalp. Patchy,
moth-eaten alopecia on the scalp
and beard area. Loss of eyelashes,
lateral third of eyebrows
Generalized lymphadenopathy.
Cervical, suboccipital, inguinal,
epitrochlear, axillary. Splenomegaly.
Mucous membranes. small,
asymptomatic, round or oval,
slightly elevated, flat-topped
macules and papules 0.5–1 cm in
diameter, covered by hyperkeratotic
white to gray membrane, occurring
on the oral or genital mucosa. Split
papules at the angles of the mouth.
Associated findings. Musculoskeletal
involvement: periostitis of long
bones, particularly tibia (nocturnal
pain); arthralgia; hydrarthrosis of
knees or ankles without x-ray
changes.
Eyes: acute bacterial iritis, optic
neuritis, uveitis.
Meningovascular reaction: CSF
positive for inflammatory markers.
Gastrointestinal (GI) involvement:
diffuse pharyngitis, hypertrophic
gastritis, hepatitis, patchy proctitis,
ulcerative colitis, rectosigmoid
mass). Genitourinary involvement:
glomerulonephritis and nephrotic
syndrome, cystitis, prostatitis.
Dermatopathology. Epidermal
hyperkeratosis; capillary
proliferation with endothelial
swelling; perivascular infiltration by
monocytes, plasma cells,
lymphocytes. Spirochete is present
in many tissues including skin, eye,
CSE.
Liver function. Elevated enzymes.
Renal function. Immune complexinduced membranous
glomerulonephritis.
CSF. Abnormal in 40% of patients.
Spirochetes in CSF in 30% of cases.
 Recurrent
eruptions appear after
month-long asymptomatic intervals.
Initially a relatively faint exanthem,
always macular, pink; lesions are ill
defined. Later lesions of early
syphilis are papular, brownish, and
tend to be more localized.
Symptoms may last 2–6 weeks (4 weeks
average) and may recur in untreated or
inadequately treated patients. Secondary
lesions subside within 2–6 weeks, infection
entering latent stage. Differential Diagnosis
Exanthem. Adverse cutaneous drug erupti
Exanthem. Adverse cutaneous drug
eruption, pityriasis rosea, viral
exanthem, infectious
mononucleosis, tinea corporis, tinea
versicolor, scabies, “id” reaction,
condylomata acuminata, acute
guttate psoriasis, lichen planus.
Clinical suspicion confirmed by
lab tests. Darkfield is positive in
all secondary syphilis lesions
except for macular exanthem.
Doxycycline 100 mg twice daily
orally for 14 days or ceftriaxone
1g IM once daily for 1014days,or,in special
circumstances,azithromycin
2gonce orally.
Desensitization,
if
desensitization is not possible,
then
erythromycin\ceftriaxone\azithr
omycin

1. FITZPATRICK’S Color Atlas and SYNOPSIS
OF CLINICAL DERMATOLOGY 7 EDITION.
 2. Illustrated Synopsis of Dermatology and
Sexually Transmitted Diseases - Neena
Khanna.
 3. Saurabh Jindal “Review of dermatology
” 2 edition, 2018.